Presser foot for sewing machines



y 0d. 13,v 1942. F. A. KUCERA 2,298,770

PRESSER FOOT FORSEWING MACHINES Frank :fucra 7 i ATTORNEYS.

Oct. 13, 1942.

` F. A. KUCERA PREssER FoQT FOR SEWING MACHINES Filed June 27, 1940 2Sheets-Sheet 2 WITNESs/i F 7gg/rml ran` acera, .y /z/ ,BY 1 v A l lATTORNEYS.

cated by the angled arrows II-II in Fig. 1.

Patented oct. 13, 1942 PRESSER FOOT FOR SEWING MACHINES Frank A. Kucera,Chicago, Ill., assigner to Union Special Machine Com n poration ofIllinois pany, Chicago, Ill., a cor- Application June 27, 1940', SerialNo. 342,653

13 claims. l, ,(01. 11e-23,5) y This invention relates to presser feetfor chain I stitch sewing machines, and ,has reference more`particularly to chaining-off felling presser feet of lthe general type,Afeatured in U. S. Patent No,

1,718,889 granted to Joseph'Berger on June 25,-:

1929, having independently movable fingers which coact with the feeddogs of the machines in advancing stitch chains connecting successivearticles passed through the machine.

Thechief aim of theA present invention is to C make it possible for apresser foot of the above type, to adapt itself more readily tothickness variations in the articles being seamed, thereby to Veasemovement of fabric beneath it incident to feeding, without impairment,however, in their efliciency as hold down means, nor interferingv withthe actionof the chaining finger or fingers (as the casemaybe) intheabsence of fabric in the sewing machine. 'I'his objective `I attainin practice as hereinafter more fullydisclosed, by constructngthepresserfoot with ytwo separate sections or componentsa toe component and a`heel component-which kare pivoted for independent movement to oppositeends of a hori- Vzontal rocker whichis in turnV pivoted at a pointintermediate its vends to the lower end of the presser bar; yand' bymounting the chaining 1ingers for pivotal movement about the fulcrumaxis of the heel component with their free ends movable up and downthrough a longitudinal fell guiding slot inthe -toe component of thefoot against the resistance of light spring pressure as compared to thatwhich influences the foot proper.

Another object of my invention is to provide `for easement ofthepressure of the footupon the Ystitch chain during chaining, so that veryne,

aswell as cheaper grades of sewing'threads, may be used without dangerof their being cut by the teeth of the feed dog. Such easement I securein practice, as also more fully set forth later herein, by providing theheel component in its bottom face with a relatively shallowlongitudinalgroove for each stitch chain which groove is aligned with thecorresponding needle in the direction of feeding.

Other objects and attendant advantages will appear from the followingdetailed description of the attached drawings wherein Fig, 1 is a viewin side elevation `of a felling presser foot con-` veniently embodyingmy invention, with the contiguous parts of the sewing machine shown in isection.

Fig. 2 is a horizontal section taken as indilscale andshowing the actionof the Fig 3 is a view .generally like Fig. 1 but the presser foot inlongitudinal section.

Fig.l 4 is .a horizontal' section takenv as indicated by the angled`arrows IV-IV in Fig. 3.

Fig. `5` shows the bottom plan View of the with presser foot.

lFigs.` 6, 7 and V8 areperspective views respectively of the toe andheel sections or components and the chaining iingersof the presser foot.

Fig. 9 is a view like Fig. 3 drawn to a larger presser foot incident tochaining o.

Fig. 10 is a View in elevation toward the left 'hand `end of Fig, 9.

Fig. 211 is a view like Fig. 9 showing the action of the presser footincident to chain feeding,

Fig. 12 is a view corresponding to Fig. 9 showing the action of thepresser footin overriding a cross seam; and

:Fig 13 .is Va `view looking toward the right hand `end of Fig. 12.

As herein illustrated, my improved presser foot oomprises'a shank memberI5 with a split collar ISwhi'ch is clamped lto the bottom end of thepresser bar Il of the sewing machine by a screw I8. `Extendingdownwardly atan inclination from ythe collar I6 of the shank member l5is a clevised' arm I9; and pivoted intermediate its ends bymeans of ascrew pin 29 which passes 'through the `opposite sides of said arm I9,is a horizontal rocker 2l in the form of a yoke with forwardlyreachingside portions 22 and a cross- Vwisefconnecting portion or bar 23 at itsrear end. `A torsion spring 24, secured by a screw 25 t'o one sidefofthe shank .member I5, has its free end fbearing downwardly Aupon thecross bar 23 of the yoked -rocker 2|.

The presser foot Yfurther includes independent toe and heel sections orcomponents 26 and 2l which are separately illustrated in Figs. 6 and 7,

Mthe former being provided with apertured up- `standing ears 23 whichare pivotally connected to the forward ends of the side arms 22` of the'yoked rocker 2| iby screws 29. The front end of the toe component 25 isturned upwardly at an i angle as at 39 to facilitate entry beneath it ofthe material M of the article which is being seamed ...in the machine,the upturned forepart 30 being `provided with an upright flange 39awhich assists in guiding the fellF of the seam. The present presser footis intendedto be used ordinarily sin association with a folder of thetype shown in "U. S. PatentNo. 1,926,950 granted to applicant-vonfSepternber 12, `1933, which is so positioned :that `itsfrontalportion provides a fell guiding wall opposite the flange 36a on thecomponent 26.

The heel component 21 is similarly formed with pierced upstanding ears3| for pivotal connection, by means of a transverse screw pin 32 to therear end of the rocker 2|, and, as shown, has its front end bentupwardly as at 33, likewise to facilitate entry of the material Mbeneath it. The heel component 21 is moreover provided in its bottomface with two narrow relatively shallow longitudinal grooves 34, seeFigs. and 10 for a purpose presently sei-l forth.

Fulcrumed for independent movement on the screw pin 32 in the intervalbetween the ears 3| of the heel component 21 are two chaining fingers 35and 36 whereof the free front or stitch chainengaging ends 35a, 36aextend into a central fell guiding slot 31 in the toe component 26,while the shank portions of said fingers pass through l clearancenotches 38 in the upturned portion 33 of said heel component. Asillustrated, the stitch chain engaging end portions 350., 36a of thefingers 35, 36 are provided with elongate clearance apertures 39, 40 forpassage through them respectively of the needles 4| and 42 of the sewingmachine, which needles are transversely spaced and offset relative toeach other in the direction of feeding. The loopers partly shown at 43and 44 in Fig. 9 cooperate with the needles 4| and 42 in a well knownway in the concurrent formation of two parallel lines of chain stitcheslongitudinally of the fell F of the seam. The chaining fingers 35, 36are subject to the downward pressure of torsion springs 45, 46 which arecoiled about the fulcrum pin in the interval between the upstanding ears3| of the heel component 21, see Fig. 2, one end of each such springengaging an anchorage rod 41 which extends crosswise between the sides22 of the yoked rocker 2|. spectively bear upon notched lugs 48, 49which project upwardly from the chaining fingers 35, 36 about midwaybetween their pivots and free ends.

Arranged to coact with the presser foot to feed the material M is afour-motion feed dog whereof the toothed portions 50 and 5|, operateupwardly in slots 52 and 53 in the throat plate 55 of the machine whichlatter has parallel bars 56 and 51 extending crosswise of said slots.

Figs. 1 and 2 show the presser foot in normal operation with the fell Fof the seam passing in the direction indicated by the arrows through theslot 31 in the toe component 26 while the side portions of the latterrest upon the material M at opposite sides of the fell, and with theheel component 21 bearing on the top of the fell with the full pressureof the usual spring (not illustrated) to which the presser bar |1 issubject.

At this time, the chaining fingers 35, 36 alsoy bear on the top of saidfell but with the lighter pressure of the springs 45 and 46, and thuscooperate normally to assist in the feeding of the material.

In Figs. 9 and 10, the material M has passedu from beneath the foot withstitch chains C, C't

trailing behind it in the direction of feeding, the needles 4I and 42being in their lowered position and the sections 50 and 5I of the feeddog retracted from the material M. Under these con-J The other ends ofthe springs 45, 46 reback down through the needle hole by the descendingneedles and into the path of the loopers with attendant breakage of thethreads, or to preclude proper subsequent formation of needle loops andresultant skipping of stitches.

When the presser foot subsequently rises in readiness to advance thechains C, C' as shown in Fig. 11, said chains are engaged only betweenthe feed dog section 5| and the heel component 21 of the presser foot,the fingers 35 and 36 having been elevated by the section 56 of saidfeed dog to substantially clear the chains. Accordingly, the advance ofthe chains, which immediately follows, is accomplished solely bycoaction between the comparatively small areas of the feed dog section5| and the presser foot heel component 21 and without the full pressureof the usual heavy spring which influences the presser bar |1 by reasonof the relief afforded by the shallow grooves 34 in the bottom of saidheel component. Thus the likelihood of the chains being cut by the teethof the feed dog is reduced to a minimum, so that very fine as well asinexpensive threads of the poorer qualities can be successively used inthe machine.

Fig. 12 shows how the toe component 26 of the presser foot and thechaining fingers 35, 36 swing about their pivots 29, 32 to allow passagebeneath them of a cross seam S in the material M while the latter isheld down under full pressure by the heel component 21. In this action,the rocker 2| will move upward about the pin 32 as a fulcrum inopposition to the pressure of the main presser bar spring. In a likemanner the heel component 21 of the presser foot will subsequently swingindependently about the pin 32 in permitting the cross seam S to passbeneath it, incident to which the rocker 2| will pivot on the screws 29While the material M is effectively held down by the toe component 26.

When the presser foot is lifted clear of the throat plate 55, thedownward movement of the chaining fingers 35 and 36 under the iniiuenceof the springs 45, 46 will be limited by engagement of their rear ends(which project rearward beyond the fulcrum pin 32), with the cross bar23 of the yoked rocker 2|, which cross bar thus constitutes a stop. Thespring 24 on the other hand will yieldingly limit clockwise movement ofthe rocker 2| about the fulcrum pin 26 so that the heel component 21will be caused to engage with the material M before the toe component 26when the presser foot is lowered.

The presser foot of my invention is, of course, not limited to twochaining fingers since by modifications well within the scope of theappended claims, the number of the fingers may be increased or decreasedto correspond with that of the needles of the sewing machines with whichit is intended to be used.

Having thus describedmy invention, I claim:

1. A presser foot for sewing machines, comprising a shank member, ahorizontal rocker fulcrumed intermediate its ends to said shank member,separate rockable toe and heel fabric engaging components carriedrespectively by the front and rear ends of said rocker; and a springpressed chaining finger having one end fulcrumed adjacent the rear endof said rocker and having its other end operating downwardly in thefield of operation of said toe component.

2. A presser foot according to claim l wherein stop means is provided tolimit the extent of downward movement of the chaining finger.

3. A presser foot for chain stitch sewing machines comprising asupporting member, a horizontal rocker pivoted intermediate its ends tothe supporting member, a toe component pivoted to the front end of therocker, a heel component pivoted to the rear end of the rocker, achaining finger also pivotally connected to the rear end of the rockerand having a free end portion operating downward in the field of actionof the toe component; and yielding pressure means influential upon thechaining finger. f

4. A presser foot according to claim 3, in which the chaining finger ispivoted coaxially with the heel component.

5. A presser foot according to claim 3, in which the rocker is providedwith a stop to limit the downward movement of the spring-pressedchaining finger when the presser foot is lifted.

6. A presser foot according to claim 3, in which the chaining nger has aprojection rearward of its fulcrum point, and in which the rocker isprovided with a stop adapted to cooperate with such rearward projectionin limiting the downward movement of the chaining nger.

7. A presser foot for chain stitch sewing machines comprising asupporting member, a horizontal rocker pivoted intermediate its ends tosaid member, a toe component pivoted to the front end of the rocker, aheel component pivoted to the rear end of the rocker, a chaining fingeralso fulcrumed at the rear end of the rocker, and having its free endoperating downward in the eld of operation of the toe component and ahelical torsion spring surrounding the pivotal axis of the rocker andhaving a free end bearing downwardly upon the chaining finger at a pointintermediate the fulcrum of the latter and its forward end.

8. A presser foot according to claim 3, in which the yielding pressuremeans bears downward upon the chaining finger at a point intermediatethe pivot of the latter and its forward end, and wherein anotheryielding pressure means bears downward on the rear end of the rocker.

9. A presser foot according to claim 3, in which the heel component hasa longitudinal groove in its bottom face whereof the depth is such as topartially relieve the stitch chain of the full pressure of the footduring chaining off in the absence of fabric or material in the machine.

10. A presser foot for chain stitch sewing machines comprising asupporting member, a horizontal rocker pivoted intermediate its ends tothe supporting member, a toe component pivoted to the front end of therocker, a heel component pivoted to the rear end of the rocker, achaining finger also pivotally connected to the rear end of the rockerand having a free end portion operating downward through a longitudinalfell guiding slot in the toe component; and yielding pressure meansinuential upon lsaid chaining finger.

11. A presser foot for use with a sewing machine having a plurality oflaterally spaced needles which are offset relative to each other withregard to the direction of feeding, a feed dog, and a throat plate withlaterally-spaced slots in which front and rear toothed sections of thefeed dog operate upwardly and with cross bars extending crosswise ofsaid slots respectively behind the several needles, said presser footcomprising a supporting member, a horizontal rocker pivoted intermediateits ends to the supporting member, a toe component pivoted to the frontend of the rocker and adapted to coact with the front section of thefeed dog, a heel component pivoted to the rear end of the rocker andadapted to coact with the rear section of the feed dog, a pair ofchaining fingers also pivotally connected with capacity for independentmovement to the rear end of the rocker and having free end portionsoperating downward in the field of action of the toe component andrespectively above the cross bars of the throat plate, and individuallyassociated yielding pressure means inuential upon said chaining lingers.

12. A presser foot according to claim 11 in which the chaining fingersextend beyond the respective needles and are provided withlongitudinally elongate apertures to clear said needles.

13. A presser foot according to claim 11 in which the free ends of thechaining fingers operate in a longitudinal fell guiding slot in the toecomponent.

FRANK A. KUCERA.

